Flight attendants should wear hats. If I had an airline, the male flight attendants would wear a garrison hat, similar to the U.S. Army 1970's envelope style caps. It might be dark navy blue with some small emblem on it. The women flight attendants would either wear the same hat or a pill box style hat similar to Lufthansa.

The pilots would wear a military style hat similar to the what many currently wear. I would not have the pilots wear a double breasted suit because that doesn't look as good if you are fat or if you unbutton the front.